Extremely low birthweight (ELBW, <1000 grams) premature infants are at very high risk for neuromotor and neurodevelopmental impairment, with reported rates of cerebral palsy (CP) ranging from 11-20%. Although cranial ultrasound (US) is currently used for brain imaging in the ELBW population, this modality cannot detect subtle brain injury that may be responsible for later neuromotor and cognitive delay. Magnetic resonance imaging (MRI) can identify brain structural abnormalities better than cranial US, and diffusion tensor imaging (DTI) may allow for detection of microstructural white matter injury consistent with diffuse periventricular leukomalacia. The power of these emerging and novel neuroimaging techniques to predict neurodevelopmental outcome among ELBW infants is not yet known, but preliminary studies are promising. We propose a multicenter, prospective study of cranial US, MRI and DTI and neurodevelopmental follow-up at 18-22 months corrected age, including neuromotor exam and administration of the Bayley Scales of Infant Development II, to assess the comparative and combined predictive capabilities of these diagnostic modalities. The NICHD Neonatal Research Network is uniquely positioned to embark upon such a project. Proper study design, execution, and development of predictive models is essential to the success of this project. To this end, we propose this research plan as an integrated part of a 3-year Mentored Specialized Clinical Investigator Development Award, during which Dr. Susan Hintz (the candidate) will complete a Master's Degree in Epidemiology in the Department of Health Research and Policy at Stanford University under the sponsorship of Dr. David K. Stevenson. Such training in outcomes research, clinical trial design and biostatistics is crucial to the development of independent clinical investigators. A mentoring committee of highly experienced perinatal epidemiologists, health outcomes researchers, and biostatisticians will guide the candidate's career development. [unreadable] [unreadable]